检索结果-南通市图书馆

Chemical composition and formation mechanisms in the cathode-electrolyte interface layer of lithium manganese oxide batteries from reactive force field （ReaxFF） based molecular dynamics

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2017年第3期11卷 365-373页

作者： sahithya REDDIVARI christian LAsTOsKIE Ruofei WU Junliang ZHANG Perimeter College Georgia State University Clarkston GA 30021 USA Department of Civil and Environmental Engineering University of Michigan Ann Arbor MI 48109-2125 USA Institute of Fuel Cells MOE Key Laboratory of Power & Machinery Engineering Shanghai Jiao Tong University Shanghai 200240 China

Lithium manganese oxide （LiMn2O4） is a principal cathode material for high power and high energy density electrochemical storage on account of its low cost, non-toxicity, and ease of preparation relative to other cathode materials. However, there are well-documented problems with capacity fade of lithium ion batteries containing LiMn2O4. Experimental observations indicate that the manganese content of the electrolyte increases as an electrochemical cell containing LiMn2O4 ages, suggesting that active material loss by dissolution of divalent manganese from the LiMn2O4 surface is the primary reason for reduced cell life in LiMn2O4 batteries. To improve the retention of manganese in the active material, it is key to understand the reactions that occur at the cathode surface. Although a thin layer of electrolyte decomposition products is known to form at the cathode surface, the speciation and reaction mechanisms of Mn^2＋ in this interface layer are not yet well understood. To bridge this knowledge gap, reactive force field （ReaxFF） based molecular dynamics was applied to investigate the reactions occurring at the LiMn2O4 cathode surface and the mechanisms that lead to manganese dissolution. The ReaxFFMD simulations reveal that the cathode-electrolyte interface layer is composed of oxida- tion products of electrolyte solvent molecules including aldehydes, esters, alcohols, polycarbonates, and organic radicals. The oxidation reaction pathways for the electro- lyre solvent molecules involve the formation of surface hydroxyl species that react with exposed manganese atoms on the cathode surface. The presence of hydrogen fluoride （HF） induces formation of inorganic metal fluorides and surface hydroxyl species. Reaction products predicted by ReaxFF-based MD are in agreement with experimentally identified cathode-electrolyte interface compounds. An overall cathode-electrolyte interface reaction scheme is proposed based on the molecular simulation results.

关键词： lithium manganese oxide batteries reactiveforce field (ReaxFF) cathode-electrolyte interface layer,molecular dynamics

Nature-based recreation for the elderly in urban areas:assessing opportunities and demand as planning support

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological Processes 2022年第1期11卷 587-603页

作者： Chen Wen christian Albert Christina von Haaren school of Architecture and Urban Planning Huazhong University of Science and TechnologyLuoyu Road430074 WuhanChina Institute of Environmental Planning Leibniz University HannoverHannoverGermany Institute of Geography Ruhr University BochumBochumGermany

Background:With elderly people comprising a growing share of the population,landscape planners need to consider their specific requirements to enhance the opportunities for them to engage in nature-based recreation(NBR).However,few studies have spatially assessed the recreation potential,demand,and opportunities for elderly people in ***,this paper aimed to spatially model and investigate the NBR opportunities for and demand of elderly people in urban areas.A spatial framework based on the EsTIMAP recreation model was developed,considering special factors to better reflect elderly people’s preferences regarding NBR at the city *** particular,NBR opportunities were assessed considering landscape aesthetics,various types of facilities,and *** street network was used to understand elderly people’s walking behaviours regarding green spaces and related ***:A case study in Hannover,Germany,demonstrated the applicability of the proposed *** results illustrate the spatial heterogeneity of recreation options for the *** parts of Hannover’s green spaces offer high recreation opportunities for elderly *** of the existing green spaces lack diverse landscape compo-nents and sufficient supply of facilities,resulting in a compromise to aesthetics and recreational ***:The proposed method contributes to research on spatial planning and environmental justice by incorporating vulnerable groups’preferences and needs in spatially assessing *** planning implications highlight pocket gardens and greenways connecting communities and parks as development opportunities in the city.

关键词： sustainability Nature-based recreation Population aging Landscape architecture GIs mapping Urban design

Genome-wide MicroRNA Expression Profiles in COPD: Early Predictors for Cancer Development

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2018年第3期16卷 162-171页

作者： Andreas Keller Tobias Fehlmann Nicole Ludwig Mustafa Kahraman Thomas Laufer Christina Backes Claus Vogelmeier Caroline Diener Frank Biertz christian Herr Rudolf A. Jorres hans-Peter Lenhof Eckart Meese Robert Bals Clinical Bioinformatics Saarland University 66123 Saarbriieken Germany Department of Human Genetics Saarland University Hospital 66421 Homburg Germany Hummingbird Diagnostics GmbH 69120 Heidelberg Germany Department of Internal Medicine Division for Pulmonary Diseases Philipps University of Marburg 35043 Marburg Germany Institute for Biostatistics Hannover Medical School 30625 Hanover Germany Department of Internal Medicine V- Pulmonology AlIergology Intensive Care Medicine Saarland University Hospital 66421 Homburg Germany Institute and Outpatient Clinic for Occupational Social and Environmental Medicine Comprehensive Pneumology Center Munich (CPC-M) Ludwig-Maximilians-University Munich Member of the German Center for Lung Research ( DZL) 80539 Munich Germany Bioinformatics Saarland University 66123 Saarbrucken Germany Center for Bioinformatics Saarland University 66123 Saarbrucken Germany

Chronic obstructive pulmonary disease （COPD） significantly increases the risk of developing cancer. Biomarker studies frequently follow a case-control set-up in which patients diagnosed with a disease are compared to controls. Longitudinal cohort studies such as the COPD-centered German COPD and sYstemic consequences-COmorbidities NETwork （COsYCONET） study provide the patient and biomaterial base for discovering predictive molecular markers. We asked whether microRNA （miRNA） profiles in blood collected from COPD patients prior to a tumor diagnosis could support an early diagnosis of tumor development independent of the tumor type. From 2741 participants of COsYCONET diagnosed with COPD, we selected 534 individuals including 33 patients who developed cancer during the follow-up period of 54 months and 501 patients who did not develop cancer, but had similar age, gender and smoking history. Genome-wide miRNA profiles were generated and evaluated using machine learning techniques. For patients developing cancer we identified nine miRNAs with significantly decreased abundance （two-tailed unpaired t-test adjusted for multiple testing P 〈 0.05）, including members of the miR-320 family. The identified miRNAs regulate different cancer-related pathways including the MAPK pathway （P - 2.3 × 10 -5）. We also observed the impact of confounding factors on the generated miRNA profiles, underlining the value of our matched analysis. For selected miRNAs, qRT-PCR analysis was applied to validate the results. In conclusion, we identified several miRNAs in blood of COPD patients, which could serve as candidates for biomarkers to help identify COPD patients at risk of developing cancer.

关键词： microRNA Cancer COPD Lung Biomarker COsYCONET

Tribological performance and microstructural evolution ofα-brass alloys as a function of zinc concentration

在线全文

学校读者我要写书评

暂无评论

Friction 2020年第6期8卷 1117-1136页

作者： Zhilong LIU Philipp MEssER-HANNEMANN stephan LAUBE christian GREINER Institute for Applied Materials(IAM) Karlsruhe Institute of Technology(KIT)Karlsruhe 76131Germany KIT IAM-CMs MikroTribologie CentrumμTC Karlsruhe 76131Germany

Tailoring a material's properties for low friction and little wear in a strategic fashion is a long-standing goal of materials *** deformation plays a major role when metals are employed in a sliding contact;therefore,the effects of stacking fault energy and mode of dislocation glide need to be ***,we investigated how a decrease in the stacking fault energy affects friction,wear,and the ensuing sub-surface microstructure *** samples with increasing zinc concentrations of 5,15,and 36 wt%were tested in non-lubricated sphere-on-plate contacts with a reciprocating linear tribometer against si3N4 *** the sliding distance from 0.5(single trace)to 5,000 reciprocating cycles covered different stages in the lifetime of a sliding *** the results among the three alloys revealed a profound effect of the zinc concentration on the tribological ***15 and CuZn36 showed similar friction and wear results,whereas CuZn5 had a roughly 60%higher friction coefficient(COF)than the other two ***15 and CuZn36 had a much smaller wear rate than *** dislocation motion in CuZn5 and CuZn15 allowed for dislocation self-organization into a horizontal line about 150 nm beneath the contact after a single trace of the *** feature was absent in CuZn36 where owing to planar dislocation slip band-like features under a 45°angle to the surface were *** results hold the promise to help guide the future development of alloys tailored for specific tribological applications.

关键词： brass tribology sliding contact microstructure stacking fault energy electron microscopy

Multimodal imaging in acute retinal ischemia: spectral domain OCT, OCT-angiography and fundus autofluorescence

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2018年第9期11卷 1521-1527页

作者： Nikolaus Feucht Daniel Zapp Lukas Reznicek Chris P.Lohmann Mathias Maier christian s.Mayer Department of Ophthalmology Technical University of Munich

AIM： To describe retinal findings of various imaging modalities in acute retinal ischemia. METHODs： Fluorescein angiography（FA）, spectral domain optical coherence tomography（sD-OCT）, OCTangiography（OCT-A） and fundus autofluorescence（FAF） images of 13 patients（mean age 64y, range 28-86y） with acute retinal ischemia were evaluated. six suffered from branch arterial occlusion, 2 had a central retinal artery occlusion, 2 had a combined arteriovenous occlusions, 1 patient had a retrobulbar arterial compression by an orbital haemangioma and 2 patients showed an ocular ischemic ***： All patients showed increased reflectivity and thickening of the ischemic retinal tissue. In 10 out of 13 patients sD-OCT revealed an additional highly reflective band located within or above the outer plexiform layer. Morphological characteristics were a decreasing intensity with distance from the fovea, partially segmental occurrence and manifestation limited in time. OCT-A showed a loss of flow signal in the superficial and deep capillary plexus at the affected areas. Reduced flow signal was detected underneath the regions with retinal edema. FAF showed areas of altered signal intensity at the posterior pole. The regions of decreased FAF signal corresponded to peri-venous regions. CONCLUsION： Multimodal imaging modalities in retinal ischemia yield characteristic findings and valuable diagnostic information. Conventional OCT identifies hyperreflectivity and thickening and a mid-retinal hyperreflective band is frequently observed. OCT-A examination reveals demarcation of the ischemic retinal area on the vascular level. FAF shows decreased fluorescence signal in areas of retinal edema often corresponding to peri-venous regions.

关键词： optical coherence tomography optical coherence tomography-angiography acute retinal ischemia retinal morphology retinal blood flow multimodal retinal imaging

RNA/DNA Ratio and LPL and MyoD mRNA Expressions in Muscle of Oreochromis niloticus Fed with Elevated Levels of Palm Oil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2016年第1期15卷 184-192页

作者： christian Larbi AYIsI ZHAO Jinliang Key Laboratory of Freshwater Fishery Germplasm Resources Ministry of Agriculture Shanghai Ocean University Shanghai 201306 P. R. China L & A Aquaculture Research and Training Centre P.O Box 2 Adukrom Akuapem Eastern Region Ghana

Palm oil is of great potential as one of the sustainable alternatives to fish oil(FO) in *** this present study,five isonitrogenous diets(32% crude protein) with elevated palm oil levels of 0%,2%,4%,6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase(LPL) and Myo D m RNA expressions in muscle of Oreochromis *** results showed that RNA,DNA content as well as ratio of RNA to DNA were significantly affected(P se the highest was recorded in fish group subjected to 6% palm oil *** was a strong positive correlation between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and specific growth rate(sGR),protein efficiency ratio(PER),while a negative correlation existed between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and feed conversion ratio(FCR).The m RNA expressions of LPL and Myo D in muscle were not significantly affected by the different palm oil levels,although the highest expression was observed in fish fed with 6% palm oil *** also existed a strong positive correlation between the m RNA expression of LPL,Myo D and sGR,PER,while their correlation with FCR was *** conclusion,elevated palm oil affected the RNA,DNA concentration as well as RNA/DNA ratio significantly,although the m RNA expression of LPL and Myo D were not affected significantly by elevated palm oil levels.

关键词： Oreochromis niloticus palm oil RNA: DNA ratio LPL MyoD gene expression

Magnetically actuated glaucoma drainage devicefor regulating intraocular pressure afterimplantation

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2023年第4期9卷 91-105页

作者： Inês C.F.Pereira Ralph J.s.van Mechelen hans M.Wyss Leonard Pinchuk Henny J.M.Beckers Jaap M.J.den Toonder Microsystems Department of Mechanical EngineeringEindhoven University of Technology5600MB EindhovenThe Netherlands Institute for Complex Molecular systems(ICMs) Eindhoven University of Technology5600MB EindhovenThe Netherlands University Eye Clinic Maastricht Maastricht University Medical Centre+(MUMC+)6202AZ MaastrichtThe Netherlands InnFocus Inc.a Santen CompanyMiamiFlorida 33186USA Ophthalmic Biophysics Center Bascom Palmer Eye InstituteUniversity of Miami Miller School of MedicineMiamiFlorida 33136USA

The key risk factor for glaucoma is increased intraocular pressure (IOP). Glaucoma drainage devices implanted in theeye can reduce IOP and thus stop disease progression. However, most devices currently used in clinical practice arepassive and do not allow for postsurgical IOP control, which may result in serious complications such as hypotony (i.e.,excessively low IOP). To enable noninvasive IOP control, we demonstrate a novel, miniature glaucoma implant that willenable the repeated adjustment of the hydrodynamic resistance after implantation. This is achieved by integrating amagnetic microvalve containing a micropencil-shaped plug that is moved using an external magnet, thereby openingor closing fluidic channels. The microplug is made from biocompatible poly(styrene-block-isobutylene-block-styrene)(sIBs) containing iron microparticles. The complete implant consists of an sIBs drainage tube and a housing elementcontaining the microvalve and fabricated with hot embossing using femtosecond laser-machined glass molds. Usingin vitro and ex vivo microfluidic experiments, we demonstrate that when the microvalve is closed, it can providesufficient hydrodynamic resistance to overcome hypotony. Valve function is repeatable and stable over time. Due to itssmall size, our implant is a promising, safe, easy-to-implant, minimally invasive glaucoma surgery device.

关键词： enable implantation overcome

GRADED MEsHEs FOR HIGHER ORDER FEM

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2015年第1期33卷 1-16页

作者： hans-Gorg Roos Ljiljana Teofanov Zorica Uzelac Institute of Numerical Mathematics Technical University of Dresden Dresden D-01062 Germany Department for Fundamental Disciplines Faculty of Technical Sciences University of Novi Sad Trg D. Obradovida 6 21000 Novi Sad Serbia

A singularly perturbed one-dimensional convection-diffusion problem is solved numeri- cMly by the finite element method based on higher order polynomials. Numerical solutions are obtained using s-type meshes with special emphasis on meshes which are graded （based on a mesh generating function） in the fine mesh region. Error estimates in the s-weighted energy norm are proved. We derive an ＇optimal＇ mesh generating function in order to min- imize the constant in the error estimate. Two layer-adapted meshes defined by a recursive formulae in the fine mesh region are also considered and a new technique for proving er- ror estimates for these meshes is presented. The aim of the paper is to emphasize the importance of using optimal meshes for higher order finite element methods. Numerical experiments support all theoretical results.

关键词： singular perturbation Boundary value problem Layer-adapted meshes Gradedmeshes Finite element method.

Effects of Trichoderma harzianum YC_(459) and soil types on seed germination and seedling growth in rock slope restoration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain science 2018年第4期15卷 730-737页

作者： MA Hoseop ETTAGBOR hans Enukwa KIM Choonsig Department of Forest Environmental Resources Institute of Agriculture and Life Science Gyeongsang National University Department of Forest Resources Gyeongnam National University of Science and Technology

We carried out experiments with various concentrations of Trichoderma harzianum YC459 in different soil types(forest soil, mixed soil,merchantable soil, and leaf mold soil) to evaluate its effect on seed germination and seedling establishment of four species(Festuca arundinacea schreb., Dianthus barbatus var. asiaticus Nakai,Lespedeza cyrtobotrya Miq., and Parthenocissus tricuspidata Planch) for rock slope restoration. We also investigated the use of drilled slanted holes on the rock slopes for seedling establishment. The results showed that T. harzianum concentration had significant effects on seed germination, seedling growth, and seedling survival for all the species with different soil types. seed germination and survival rates peaked at 5% T. harzianum concentration with leaf mold soil and decreased as T. harzianum concentration increased from 5% to 10%. seedling survival rates of all four species were generally lowest at 0% T. harzianum concentration in all soil *** height of F. arundinacea and L. cyrtobotrya peaked at 5% T. harzianum concentration whereas that of D. barbatus and P. tricuspidata peaked at 10%T. harzianum concentration. We concluded that 5% T. harzianum concentration with leaf mold soil is appropriate for seed germination and seedling survival rates of most species, thus enhancing seedling establishment. Practical application of the findings of this study will contribute in the vegetation restoration of steep rocks in mountain environments.

关键词： Dianthus barbatus Drilled holes Festuca arundinacea Lespedeza cyrtobotrya seedling establishment seedling survival